Induction automatic stop and cab-signal system.



c. L. BOPP. l l INDUCTION AUTOMATIC STOYPAND CAB SIGNAL SYSTEM.

APPLICATION FILED JULY .26, 1912.

f Patented Dot. 2U, 1914.

4 SHEETS-SHEET 1.

ifi

witness@ l C. L.' BOPP.

INDUCTION AUTOMATIC STOP AND'OAB SIGNAL SYSTEM.

APPLICATION FILED JULY z'e. 1912. 1,1 14,430. f Patented 0.312,0,.1914

4 SHEETS-SHEET 2.

C. L. BOPP. INDUCTION AUTOMATIC STOP AND GAB SIGNAL SYSTEM.

APPLICATION FILED JULY Z6, 1912. 1,-1 14,430. v Patented oct. 2o, 1914n4 SHEETS-SHEET 3.

(22725027 l.. 5gg/0'.

attorneys o. L.l BOPP. INDUCTION AUTOMATIC STOP 'AND CAB SIGNAL SYSTEM.

APPLwATIoNI'ILED' JULY 26.1912. y Patented 0013. 20, 1914 4ASHEETS-SHEET 4.

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@Zi/M100 L. 9o/0,0.

CLINTON L. BOPP, OF WATERLOO, IOWA.

INDUCTION AUTOMATIC STOP AND CAB-SIGNAL SYSTEM.

Specification of Letters Patent.

Patented Oct. 20, 1914:.

Application led July 26, 1912. Serial No. 711,746.

To all whom it may concern.'

le it known that I, CLINTON L. BOPP, a citizen of the United States,residing at Waterltilo, in the county of Blackhawk and State of Iowa,have invented certain new and useful Improvements in Induction AutomaticStop and Cab-Signal Systems; and I do hereby declare .the following to.be a full, clear, and exact description of the invention, such as willenable othersskilled inthe art to which it appertains to make and usethe same.

This invention relates to improvements in railway signaling systemswhere the principle of magnetic induction is employed to set intooperation mechanism which will indicate the condition of the line.

VAn object of the invention is to provide a simplied system to breakcircuits which require no insulation between adjacent blocks' and whereno,` current flows except when a train is in the system.

' Another object of the invention is to provide-a inagnetically actuatedneedle for reducing the resistance of a cab signal circuit so thatsignal circuits may be closed as the needle isy actuated.-

With these and various other objects "which will appear as thedescription proceeds, the invention resides in thecombination'andarrangement of parts shown and vdescribed more/fully inthe following speciication and claims.

Inthe drawings: Figure 1 is a diagrammatic viewof 'a section of railwaytracking .showing the saine divided into four blocks with wiring. Fig. 2is a similar diagrammatic view showing the track with one train in thesystem. Fig. 3 is a similar diagram- ,matic View showing two trainstraveling in the saine direction. Fig. 4 is a similar diagrammatic viewshowing two trams 1n adjacent blocks approaching each other. Fig. 5 is aview, part in elevation and part shown diagrammatically of thelocomotive equipment when'the same is set to indicate safety. Fig. (3 isa view similar to Fig. 5 showing the locomotive equipment set when theline is in Fig. 7 is a section through a casin in which is mounted animproved time rake setter. Fig. 8 is a fragnlontani vicw slimving thelocationlof the magnetic needle relative to the wheel of the lmoniotive.Fig. S) shows a modified .View o the needle. Fig. l() showsfdetall viewof one of the fuses used in the invention.

This invention depends upon the well known electrical phenomenon that ainagnetic needle suspended in a magnetic field set up by current flowingthrough a wire will be deflected at an angle to the wire. Another factWhich is made use of in the present invention is that high potentialcurrent will jump the shortest air gap thrust in its path. The generalarrangement of the invention isA to provide a needle deflected bycurrent flowing in a conductor, a source of high potential currenthaving an air gap in its circuit which is ,to be regulated by the needleas it swings and certain local circuits designed to be broken as thecurrent flows in the high potential circuit. l

. In order that the invention may be better understood, the conditionsof the track circuits will be traced first.

By referring to Fig. 1, where normal conditions of the track system areshown, it will be seen that rails 1 and 2 are connected respectively topositive and negative poles of a plurality of line batteries, 3, 4, 5,and 6.

The rail l is connected to the positive poles of the batteries 3, 4, 5,and 6 by means of wires 7, 8, 9 and 10 respectively, and the negativepoles are connected to rail 2 by means of wires l1, 12, 13 and 14respectively. It will be seen from the matter illustrated in Fig. 1 thatno current normally flows between the two tracks, or if any current doesflow due to leakage it,will be so infinitesimal as not to affect theoperation of the system. The points where wires 7, is', 9 and l0 connectwith rail 1 define blocks A, B, C and D. f

Referring to Fig. 2, it will be seen that train T\has been shown ashaving entered block C,\1nd that a magnetic needle is carried overglail1 in front of the foremost right wheel, said needle being shown moreclearly in Figs. 8 and 9. When the train '.l is in the position shownall of the batteries in the line will feed through the axles ol saidtrain, the batteries 3 and l together with all those to the left of 3feeding through rail 1, and under the needle, while batteries 5 and 6together with all batteries to the right of battery 6 feed through theaxles of train T withoutv passing under the needle. Under theseconditions therefor, the batteries in the blocks ahead of the block-pointe .train T has moved to b occupied by the train furnish' thecurrent which deflects the needle carried by the flow through the axlesof the train T without affecting the needle carried by the train T.Inasmuch as each of the trains T and T eat many axles, the resistance ofthe 1 has a path ronirail 1 t0 rail 2 will be so exceedlngly 1liir' thatit may be considered neglig le and that the said rails areshort-circuitedat the point where the wheels contact. With respect toFig. 3 therefore, it will be seen that the parts of the track extendingbetween the two trains are short l eircuited and that no difference ofpotential exists between the rails 1 and 2 in this part of the track byvirtue of eitherA the set of batteries to the leftor to the right of thesection. The only current which can fiow through the rails of the trackbetween the two trains is that furnished by battery 4.

Tracing the circuit from battery 4, it will be seen that at the pointwhere wire 8 is connected to rail 1, two paths are open to the current,one of which leads forward to the train T and across to the left handside of train T, while the other path leads back through rail l to trainT across to the other rail 2, and forward to the left hand Side of trainT. As shown in Fig. 3 it might be estimated that the first of thesepaths is approximately one-third the length of the second path, it beingremembered that the resistance of the train is negligible. Since in adivided circuit current in the various branches will vary inversely as;the resistance of those respective circuits, itlgis obvious that thecurrent, through the first of the above circuits will be three times thecurrent in the second circuit traced. It might be considered that thecurrent in wire 8 was divided so `that three-fourths took the shorterpath, whereas one-fourth took the longer path.v

Hence, when two trains are traveling in the samev direction andl are inadjacent blocks, the train ahead will have its needle deflected, whilethe rear train will be traveling over the track which is carryingcurrent insufficient to operate the needle carriedby said rear train.

Referring to Fig. 4, it will be seen that as pointed out in the aboveparagraph, the battery 3 and all batteries to the left thereof will feedthrough train T in block B, but inasmuch as train T i's moving to theright the current from battery 3 will not effect the needle carried bytrain T. Similarly, batteries 5 and 6 together with all the batteries tothe right of battery 6 will flow through train '1" without affecting itsneedle. As before the current from battery 4 will divide, the lessercurrent passing through the longer circuit. Inasmuch as the trains areapproaching each other, their needles will be located over the dividedcircuit in which the weaker current is flowing, hence neither of theneedles will be' deflected, giving the signal to each'engineer. Shouldtrain T be just in front of the point where wire 7 connects with rail 1,and train T' be just in front ojf the point where wire 8 connects withrail 1, then, as in the case just described, battery 3 and the batteriesto the left thereof will not affect the needle carried by train T. Also,battery 5 and all batteries to the right thereof will not affect theneedle carried by train T. There will be two paths open for the flow ofcurrent from battery 4, viz., battery 4, wire 8, over the upper rail ofblock B, through the train T to wire 12, back to battery, train T beingclose to .the point of contact between wire 12 and rail 2. The othercircuit is; battery 4', wire 8, through train T', 'over the lower railof block B,.up wire 12, and back t-o battery 4. But these circuits areof substantially equal length, therefore the currents flowing throughSaid circuits are substantially equal; The needles carried by thetrains'are so designed as not to be' "ilefiected far enough when halfcurrent flows to keep conditions normal and the needles will thereforetend to aline with the rails, as hereinafter described. From thesevarious circuits, it will be seen that .when trains are in adjacentblocks and traveling in the same direction. the rear train will be.given a signal through its needle, the condition for giving a signalbeing that the needle shall not be deflected by a current in the railand further that if two trainsl be in adjacent blocks and approachingeach other, neither needle will be deflected and both `trains will begiven a signal.

The magnetic needle associated with the mechanism shown diagrammaticallyin Figs. 5 and 6 islocated just in front of the first right hand wheelof the locomotive looking in the direction of travel. From this it willbe seen that when two trains approach each other as shown in Fig. 4,part of the rail which is directly under the needle containing easeshown in Fig. 8 is not carrying the normal currentv necessary to deflectthe needle fully, the result of which is to allow needle contained inthe case to line up with the rail, which will be described more fullyhereinafter.

Referring now to Fig. 5 it will be seen lao Aio

that a section ofthe rail is indicated at 16,l switch 17 being shown incircuit with battery 18 for the purpose of making-and Abreakingcii'cu-it'through rail 16. This diagrammatic means ofl showing themaking and reakingof vcircuit throughlG is 'shown in Fig. 5721s a simplemeans of sending current through the rail section 16 which conditionIwill necessarily be assumed in describing the operation of the cabcircuits. Shown pivotally mounted at` 19 is a magnetic needle A20 of.greater length than the width of the tread of rail 16, the needle 20adapted t0 such as for instance a coil, mounted to -swing above therail, the coil having a discharge point' which is adapted to swing inclose noximity to strip 21. In either event, the discharge point uponthe swinging nieinber is to be provided with platinum vor, othernon-oxidizing metal, which is .not

readily eaten away'by thel passage of a high :potential spark.

If so desired, an astatic zcouple, such as is illusti'atcdin Fig. 9, mayused as a moving member, Vthe-fadfvaiitage .of using'said couplebeingthat it.

isyvey much more sensitive than afsingle :needle,v and therefore wouldyield` to a much weaker current hm'ing in the'rail.v `Although thesevarious modifications have any needle capable of being deflected by beenreferred to, it is to be understood that such-a curi-ent as wiilrailgmay'be used. l .Byrefcrring to'Fig. 5 it willbe seen vthat twomechanisms aside from the ina` etic needle generally indicated at Nfares Own, the `first mechanism beingr the source of cunrcnt supplyshown at l, and the secondfa fuse distributing mechanism F. Themechanism l comprises a generator 22 having normally flow in the brushes23 and 24 mounted upon a shaft25.

l 'Ih-ere isalso mounted upon shaft 25 a coniii'iutatorf-v26 havinginsulated sections 4V27 and 28, these insulated sections being"`designed vto breakrcircuit through brushes 29 and-3() as the generatorrevolves upon-shaft 25. lf the moving car upon which the mechanismisfloeated be a strain loi-.ometlve a turbo generator set can be used todrive gene-'l rator 22, while if the mechanism be installed upoufianelectric. locon'iotivel suitable trailsniecl'ianismjust describedfurnishes direct current. induction coil or other high potenliafapparatus 321s designedto furnish' alternating currentof high pressure,primary '33 of said induction coil being excited from the generatorthrough connnutator by the following circuit: Brush 24, wire 34, primaryY33, wire 35 brush 30, interrupter 26, brush 29, wireA36, brush 23, backto the commutator of the generator. It will be secu that insomuch as'interrupter 26 is inserted in this circuit, the current is vcontinuouslyinterrupted so long as motor 22 revolves, the result of which is tofurnish the primary of the induction coil with a' iiuctuating current,whereby an alternating current is produced in the secondary 33 of Saidcoil.

At F is-shown a usedelivering mechanism provided with a statitnarymember 37 and a sliding member 38. tationary/m m ber 3T is composed of ahousing 39 in w ich t are piled a series of fuses40, said/f being ofordinary construction' and/having metallic ends separated by 'a strip-of-insulation, said ends bein connected bymeans of fusible metalcarried by the insulation. (See Fig. 10.) Brackets 41 and 42 are rigidwith member 37 but insulated thoroughly therefrom, the object ofsaid-insulationbelv ing .to prevent any jumping of currentl frome thesecondary ofthe induction coil' tof,v the housing 39. vBracket41-,carrie`s a regulablef idischarge member 43,:whilevva similar regu-V`y i labledischarge member is .fcarriedubly f bracket 42.Afspringpcontac't -45 is Acarried on the side of the housing); AThesliding. l

member 38 comprises insulating 'bei seh-av-Jl l g ing an upraisedportion 63nd 'h'ayiifi'g tvvvoA contact plates 47. and,48seeured tothelin'si'il lating base. A third contacty plate 'T49 Vex-k tending thefull length of the movable member 38 is. provided central-Iofsa'id;movable.-

,member and serves 'as a common vconductor foncurient passing throughplates 4f( and 48. Flexible springs @carried by but insu'- ilated fromstationary member 37 aregprml vided with depending lugs which: Li'n'tolsuitable recesses formed intheimetiallic'ends of the fuses foi removing'the saine, whichy after. y. l'For the purpose tof,v clearnesg, the'snpportsjor the-springs .to '.the vfr';ight' ,of

understood that y,thigag-supports upon each side -of the fuse holderAare identical.-'Pa'rtM4 146;, is raised above the contactfplates'i? andv483,

just 'enough to `retain one of tlie .fuses"40 upon thc Contact plates asthe member v-38 slideslmder stationary member 37. .Pivoted as at 52 is alever 53 having a bifurcated end 54 which is' `designed to engageapinfgu' carried by the movable'4 member 38,. v'v'hli'c constructionadmits of the-moizingo'f m'ni swinging of the needle 20 will be traced.It will be assumed that the lcurrent is owing 1n rail 1G, that needle 20is deflected as indicated, and that the fuse delivering mechanism F isin the position shown in Fig. 5. With current flow-ing in rail 16 it isAdesired to show that safety will be indicatedby the that magnet 60 isenergized and. that as a.

result armature 65,secured rigidly to lever 53 is attracted to the saidelectro-magnet. There is also a second circuit contemporaneous with theone just traced which is as follows: Brush 24, wire 56, electro-magnet57, wire 58,' wire 66, electro-magnet 67, wire 68, contact plate 47, thepile of fuses 40, contact plate 49, wire 63, wire 64, back to generator22 by way of brush 23. Current flowing in this circuit will energizemagnet 67 and it will be seen that the air gap between wthe armature 69secured rigidly to the lever 53 is greater than that betweenelectro-magnets 60 and armature 65, the natural result of which is thatlever 53 will remain in the position shown so long as electro-magnet 60is energized. The lever 53 carries a spring p contact 70 which, as shownin Fig. 5, makes contact with contacting screw 71, which causes thefollowing circuit: Brush 24, wire 56, wire 72, wire 73, contact brush45, wire 74, lever 53, contact sprin 70, contacting screw 71, wire 75,contact 76, armature 77, contact 78, wire 79, electro-magnet 80, wire81, wire 82, to junction 83, Where current divides, part of it goingthrough wire 84, electro-magnet 85, wire 86, wire 87, back to thegenerator by meansl of brush 23, and part of it going from the junction83 to wire 88, white light 89, wire 90, wire 87, back to brush 23`ofgenerator 22. Thus, s'o long as contact spring 70 engages contact screw71, a current` will' be maintained through electro-magnet 85fiwhichcontrols the'brakes of the train and clear light 89.

To explain further the operation of the mechanism it will be assumedthat current has failed in the rail 16 under such conditions as areindicated in Figs. 3 and 4, the necessary result of which will be thelining up of ythe magnet 20 with rail 16. When this is done it will beapparent that the air gap between needle 20 and the strip 2l'\vill beyAconsiderably enlarged. The air gap regulator is placed considerablycloser to the fuse 91 than airgap regulator 44 is to fuse 62. It will beseen that when air gap 92 is placed in series with variable airgap 93 atthe needle, high potential current will pass through wire 94, wire 95,manually operated switch 96, contact 97, wire 98, strip 21, and willjump gap 93, when needle 20 is as shown in Fig. '5, will pass throughthe needle 20 to wire 99, down air gap regulator 43, will jump gap 92,will pass to strip 49, wire 63, back to secondary. The sum of thelengths of the air gaps 92 and 93#with needle 20, as. is shown in Fig.5, are designed to be less than air gap 101 which is between air gapregulator 44 and fuse 62. As needle 20 swings, however, the sum of theair gaps 92 and 93 will exceed the vlength of air gap 101 so that theresistance of the air gap in the circuit .containing air gap 101 will beless than the resistance of the air gap of the circuit just traced.Under these conditions the following high potential circuit will be .setup: Current will start from secondary 33 of the induction coil, passthrough Wire 94, wire 102, spark gap regulator 44, air gap 101, plate49, wire 63, back to the secondary of the induction coil. As shown inFig. 5 the fusible art of the fuse 62 is directly in the path ofp airgap 101 so that as current flows in the circuit just traced the fusewill be melted and the circuit containing electromagnet 60 will bebroken. With electromagnet 60 denergized and magnet 67 still energizedthe sliding member 58 will move to the new position indicated in Fig. 6.lnsomuch as magnet 67 will attract armature 69 formed rigid with lever`53 the conditions just traced-are desired to be accompanied by a signalshowing that the line is in condition of danger, such indication beingcontemporaneous with condition of no current in rail 16. As lever 53swings to the new position shown in Fig. 6, contact spring 70 wi'll.contact with contact screw 100, when the following circuits will becompleted: Brush 24, wire 56, wire 72, Wire 73, contact spring 45, wi're74, lever 53, spring Y70, contact screw 100, wire 103, Wire 104, redlamp 105, wire 106, wire 90, wire-87, brush 23, back to generator 22.Current flowingin this circuit will light red light 105, the burn-` ingof ight 105 being caused by the making of con acts 70 vand 100 whichnecessarily broke contacts 70 and 71'. Insomuch as. 'contacts 70 and 71were in series with electromagnet 85`and clear light 89,V it will beapparent that the latter mentioned devices will be inoperative.

In order, to complete the cycle of opera tion it will be necessary toassume that current is again flowing in rail 16, the natural result oftvhich will be to deflect needle 20 until th/e same is in the position.shown in Fig. 5. The mechanism at F under this consideration will be asshown in Fig. 6, where-` as thb needle will be shown as in Fig. 5. Itwill be seen that as shown in Fig. 6 the spark gap 92 has interposedtherein the fusible dition. Just as soon as the needle 20 becomes close,enoughv to strip: 21 'to reduce the sum of the airk gaps 92 and 93 to alength less than air gapV 101 the current will of cenare lrake a shorterpath and flow through the two air ga s 92 and 93. The flowing of currentthrong air ap 92 and the circuits which have already een traced willresult in the fusing of the fuse 91, which fuse is in series with theelectro-magnet ,67, so that said electro-magnet is denergized. It willbe noted, however, that pile of fuses 40 is under this presentconsideration in such a position as to make the circuit containingmagnet complete, so that said magnet will be energized, the naturalresult of which is to attract: armature (i5 and throw the mechanism inthel position shown in Fig. 5. Se tar the description has shown acomplete cycle of the signaling apparatus in normal conditions when nobad fuses have been delivered, and when the generator has beengenerating continuously, and when there is a sutiiciency of fuses inhousing 39.

If at any time one of the fuses bridging plates 47 and`48 had been blownor a defective fuse had been delivered by the mechanism F, then the pathof the circuit leading to the ,magnets and 67 would have been opened. Itwill be seen that if the path of magnets (30 and 67 is opened itynecessarily follows that magnet 57 will also be opened the result ofwhich will be the dropping ot arn'iature 77, which will close contacts107 and 108. `When this contact is made the following circuit is made:Current will start from hrnsh'fl, wire 56, wire 105).,contact 107,armature 77, Contact 108, wire`Ll0, wire 103, wire 104,1' d light 105.wire 10(3,wire $10, wire 87, brush 2.- back to generator 22. Thus, itwill be seen that in the event ol the mechanism F delivering a defectivefuse the same wili be indi ated 4to the engineer by the lighting of -dlight=105. Should the dynamo fail to Lop'erate, no cin-rent will he fedto electroanagnet 85, the result of which will be the deinergizalion ofsaid magnet with the conseuluent setting of the brakes to be describedhereinafter. l

.t weight '111 is mounted in housing 37 upon the "pile otV fuses 40 forthe purpose of hoiding said fuses as each successive fuse is tai-:cnvfrom the bottom of the ile. Of course a spring could be used for thissame purpose, but in either event it would be desirable to haveprojections 112 carried by the means for pressing the fuses into place,the pari-ose of which would he to contactwith' spring when the fusesupply was low to break contact between spring 45 and wire '1,71 and tomalte contact between spring 45 and wire 113. lVhen this last; mentionedcontact is made the following circuit will be completerlaf/brush 24,wire 56, wire '72, wire 72" spring 415,y yyvire 113, wire 104, the redlight V105. wil-e106, wire 90, wire 87, brush 23, back to the generator22. Current flowing in this circuit which is closed when the fuse supplyhas been exhausted or about to be exhausted will light red light 105which is an indication that part of the mechanism is in need ofattention. As shown in either Fig. 5 or (5 a spring ejector .'10provided with a depending point 51 is carried by bracket 41 so that asthe swinging member 38 slides under stationary member 37 the point 51will engage the fuses. To the right of Fig. 5 where the fuse ejectingmechanism is duplicated it will he seen that depending lug or point 51is in such a position that when member 38 swings thc fuse (S2 will becarried to the position indicated in Fig. 6. Upon the next oscillationof the fuse delivering mechanism a dead fuse will be carried out by thepoints of lugs 51 and will force olf of the contact strips 48, and 49the first fuse 62, thereby providing for the automatic ejection of thedead fuses. It is to be borne in mind of course that the Contact betweenthe bifurcation 54 and the pin 55 is to be insulated so that no currentcan pass from lever 53 to the fuse delivering mechanism'F.

From the circuits traced it will be seen that magnets 80 and 85 arethrown across generator 22 in series so that if either of said magnetsbecome denergized it will be accompanied by the simultaneous denergi-Zation of the' other. A spring actuated armature 114, suitably pivotedto the frame of they ocomotive and provided with a notch 115 is designedto be held in an upward position by electro-magnet S0 so long as the,said magnet is energized.` A spring actuated lever 116, suitablypivoted to the locomotive. is designed to be released by the patch115.115 electro-magnet S0 attracts arm-v ature 114. .\s the lever 116 isreleased it will be drawn by a spring 117 against a manually operablebutton 1.18, by means of which said lever can be made to close contactwith contact. point 119i Insoinuch as he brake setting means, which isoperated y electro-magnet S5. is time controlled, it will be possiblefor the engineer to prevent -the setting of the brakes afterelectro-magnet S0 has been denergized by simply pushing 'manuallyoperable button 118, which will -close the following circuit: brush 24,wire 56, wirc 72. wire 120, lever 116, contact point 119, wire 121, wire82, wire 84, electro- 'magnet 85. wire S6. wire 87. brush 23, back togenerator 22. From the circuit it will be seen that current flowing asindicated will lenergize electro-magnet 85, a result ot' which valve124. The pawl-lever 122 pivoted to `the frame at 125 has at one end amovable weight 126 for adjusting the balance of the lever so that saidend carrying the weight will descend as electro-magnet 85 is denergized.The other end of the lever 122 which is provided with a catch 127,engages a ratchet wheel 128rigidl secured to a cani 129 mounted upon saft 130. Formed integral with cam 129 is a weight 131 the purpose ofwhich is to rotate the cam 129 as pawl-lever 122 is raised from ratchetwheel 128, by descent of weight 126. A suitable opening 132, formedbetween the weight 131 and cam 129 shows a graduated scale 133 wherebythe rate of rotation can be roughly estimated by the engineer. Part ofthe cam 129 is formed' with teeth as at 134, for the purpose of engaginga inion 135, said pinion carrying with 1t a an 136, whereby the descentof weight 131 is restrained from being too rapid. Pi"- oted to the airbrake 124 as at 136 is a. screw carrying arm 137 the outer end of whichis pron'ded with a roller 138, for engaging cam 129. As the cam 129rotates under the influence of weight 131` the roller 138 will rest uponthe surface 139 of cam 129 until portion 140 arrives under the roller138, which condition will result in the dropping of arm 137 and theconsequent drop ing of iston 140 mounted in the air bra e caslng 124.The valve 141 which is loosely engaged by pistonA 140 will, as a resultof the dropping of piston 140. open a passage bctween air pipe 142 andexhaust pipe 143. In this way it will be seen that the air brakes may beset by the denergization of electro-magnet 85 after an desired intervalof time has elapsed, sai time being dependent upon the Asize of fan 136.Pivoted about shaft 130 is an engineers lever 144 having mounted thereina rod 145 provided with a teeth engaging point 146 and sliding withinsaid lever 144. A spring 147 carried within lever 144 is designed tohold point 146-normall 128, but sai point may be forced into en- Agagement with said Wheel by means of ed across said air gap, a regulableair V1n multiple with the variable air gap, a use away from the ratchetWheel he wishes, the fan 139 not interfering with the return movement ofcam 149.

lVhat I claim is: 1. In a railway signal system, a variable air gap, asource of high potential connectlocated in the regulable air gap, anelectric device, a source of current, a closed circuit including thefuse electric device and source of current, and means for varying thelength of the variable air gap, the length of the variable air apadapted at times to exceed thelength o? the regulable air gap.

2. In a railway signal system, a source of high potential an electrodeconnected to one si c of said source,'a magneticneedle connected to theother side of said source and adapted to have one end thereof swing inproximity to said electrode, an air gap conncctcd in multiple acrosssaid electrode and magnetic needle, a closed circuit, a portion of saidcircuit being fusible and located within the second mentioned air gap,electro magnetic means for deflecting the needle, the distance betweenthe/needle and electrode adapted ut times to exceed the' length of thesecond mentioned air gap,

3. A variable air gap, a regulable sur. gap, a source of high potential,means ,for connecting said gaps in multiple across the source of highpotential, a closed signaling circuit, a portion of said circuit beingfusible and located within the second air gap and means for varying*ythe length of the variable air gap, the variable air gapfadapted attimes to exceed the length of the second air gap.

4. In an electric signaling system, an electric current conductor havingmagnetic properties, a magnetic needle, an electrode, a source of highpotential connecting thc electrode and needle, an ailxgap connectedV inmultiple across the electrode and magnetic needle, a closed circuit aportion of said circuit being fusible and located within the air ga i,said magnetic needle being no1-mall de ected by current assinlg in thecon uctor to have one end adljacent-the electrode, said needle adaptedto alinewitli the conductor whenno current is flowing inY in presence otwo witnesses.

CLINTON L. BQPP. lVitnesses F. W. EKLUNY H.y Il. S0110.

